little colorado river tmdl for turbidity · september. two usgs gauge stations are present on lcr....

A r i z o n a

LITTLE COLORADO RIVER

TMDL FOR TURBIDITY

AUGUST 2002

Department of Environmental Quality

Little Colorado River TMDL for Turbidity August 2002, ADEQ

Table of Contents

LIST OF ABBREVIATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1 BACKGROUND INFORMATION1.1 Geography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71.2 Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71.3 Hydrology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71.4 Climate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81.5 Vegetation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81.6 Land Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2 ENDPOINT IDENTIFICATION2.1 Turbidity and the Linkage of Water Quality Standards and Pollutants . . . . . . . . . . . . 112.2 Identification and Description of Pollutant Sources . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.2.1 Point Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112.2.2 Non Point Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.2.2.1 Grazing and Wildlife . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112.2.2.2 Stream Channel Instabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . 122.2.2.3 Road Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122.2.2.4 Golf Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122.2.2.5 Natural Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.3 TMDL Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132.3.1 TSS Equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132.3.2 Background Site Location and Values . . . . . . . . . . . . . . . . . . . . . . . . . . 152.3.3 Consideration of Seasonal Variation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162.3.4 Margin of Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172.3.5 Winter-Spring Flow Based TMDL Values . . . . . . . . . . . . . . . . . . . . . . . 172.3.6 Summer-Fall Flow Based TMDL Values . . . . . . . . . . . . . . . . . . . . . . . . 19

2.4 Waste Load Allocations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202.5 Load Allocations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

3 IMPLEMENTATION3.1 Best Management Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223.2 Monitoring Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253.3 Time Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263.4 Milestones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26


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3.5 Assurances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4 PUBLIC PARTICIPATION4.1 Public Participation in the TMDL Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274.2 Watershed Group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

APPENDIX A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

List of Figures

Figure 1 Project Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Figure 2 Representative Ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Figure 3 Land Ownership . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Figure 4 Land Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Figure 5 Winter-Spring, TSS vs. Turbidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Figure 6 Winter-Spring, TSS and Turbidity vs. Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Figure 7 Summer-Fall, TSS vs. Turbidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Figure 8 Summer-Fall, TSS and Turbidity vs. Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Figure 9 Daily Average Discharge (1940-2000) for the Little Colorado River . . . . . . . . . 17

List of Tables

Table 1Summary of Turbidity Data on LCR Used to Make Listing Decisions . . . . . . . . . . . . . . . 5Table 2TMDL Summary Table for the Little Colorado River . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Table 3Calculation of Background Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Table 4Calculation of Target Load for Winter-Spring Flows . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Table 5Calculation of TMDL for Winter-Spring Flows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Table 6Calculation of Measured Loads for Winter-Spring Flows . . . . . . . . . . . . . . . . . . . . . . . 18Table 7Calculation of Load Reductions for Winter-Spring Flows . . . . . . . . . . . . . . . . . . . . . . . 19Table 8Calculation of Target Load for Summer-Fall Flows . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Table 9Calculation of TMDL for Summer-Fall Flows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Table 10 Calculation of Measured Loads for Summer-Fall Flows . . . . . . . . . . . . . . . . . . 20Table 11 Calculation of Load Reductions for Summer-Fall Flows . . . . . . . . . . . . . . . . . . 20Table 12 Load Allocation and Load Reduction Targets by Source . . . . . . . . . . . . . . . . . . 21Table 13 Estimated Implementation Schedule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26


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LIST OF ABBREVIATIONS

ADEQ - Arizona Department of Environmental QualityADHS - Arizona Department of Health ServicesAGFD - Arizona Game and Fish DepartmentALRIS - Arizona Land Resource Information SystemAZ - ArizonaBLM - Bureau of Land ManagementBMP - Best Management Practicescfs - Cubic Feet Per SecondEPA - Environmental Protection Agencyft - Feetin - InchesLA - Load Allocationlbs/day - Pounds per DayLCR - Little Colorado Rivermg/L - Milligrams Per Litermgd - Millions of Gallons Per DayMOS - Margin Of SafetyNTU - Nephelometric Turbidity UnitsQ - DischargeTMDL - Total Maximum Daily LoadTSS - Total Suspended SolidsUSEPA- United States Environmental Protection AgencyUSFS - United States Forest ServiceUSGS - United States Geological SurveyWLA - Waste Load AllocationWQS - Water Quality Standard


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EXECUTIVE SUMMARY

Section 303(d) of the Clean Water Act requires that States develop Total Maximum Daily Loads(TMDLs) for surface waters that do not meet, and maintain, applicable water quality standards(WQSs). A TMDL sets the amount of a given pollutant that the water body can assimilate withoutcreating an impairment of that surface water’s designated use. The TMDL by definition (40 CFRPart 130) is the sum of all Waste Load Allocations (WLAs) (point sources) and Load Allocations(LAs) (non-point sources) with the inclusion of a margin of safety (MOS) and natural backgroundconditions.

The Little Colorado River (LCR) is located in southern Apache County, AZ near the border withNew Mexico. Its headwaters originate in the White Mountains along the northern and easternslopes of Mount Baldy (11,043 feet (ft.)) (Fig. 1). The river flows east-northeast until it reachesEagar, AZ where it turns to a more northerly course. Two segments, totaling 16 miles, of the LCR,near Springerville, AZ, were listed as impaired due to violations of the turbidity standard forAquatic and Wildlife coldwater streams, which is 10 NTU. The first segment, Water CanyonCreek to Nutrioso Creek (HUC 15020001-010), is 4 miles long. The second segment, NutriosoCreek to Carnero Creek (HUC 15020001-009), is 12 miles long.

The LCR was placed on the 303(d) List based on sampling taken from 1991 through 1996 (seeTable 1). From June to October 2000, the Arizona Department of Environmental Quality (ADEQ)conducted an intensive turbidity study of the LCR. Eighteen monitoring sites were established alongthe LCR from the intersection of Highways 260 and 373 (near Greer) to the end of the listed reach.The results indicate that the turbidity impairment actually starts upstream of the confluence of theLCR with Water Creek Canyon (Site 35). Field observations indicated that the main cause ofturbidity is loss of vegetative cover due to historic and current grazing practices. The loss ofvegetation, especially riparian, allows increased runoff, soil erosion, and bank destabilization.

The turbidity impairment appears to be directly correlated to large flow events that occur during theWinter-Spring rain/snowmelt season and during the Summer-Fall monsoon season. Thesecorrelations were developed based on United States Geological Survey (USGS) historic flow datafor the LCR. TMDL values were developed for each season to reflect these differences in flowregimes and resultant sediment delivery mechanisms. Because turbidity is a dimensionless unit, sitespecific TSS versus turbidity correlations were created for this TMDL. These correlations link TSSvalues in milligrams per liter (mg/L) to turbidity standards and measurements. Target LoadReductions of TSS will equate to reductions of turbidity.


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Table 1 Summary of Turbidity Data on LCR Used to Make Listing Decision

Segment Agency ProgramSite Description

Year -Number of

Samples

ResultsRange1

(NTU)

Samples ExceedingStandards

(Exceedance Rate)

Water Canyon- NutriosoCreek

ADEQ FSNHwy 60 Bridge (TMDLsample site 90)

1994 - 61995 - 61996 - 6

7.06 - 96.4 12 of 18 (67% exceedance)

Nutrioso Creek- Carnero

ADEQ BiocriteriaBelow Nutrioso

1992 - 1 16.2 1 of 1(100% exceedance)

ADEQ FSNBelow Springerville

1991 - 51992 - 61993 - 3

3.9 - 47 7 of 14(50% exceedance)

1 TheWQS for turbidity is10 NTU.

The target load capacity for the LCR during the Winter-Spring seasonal flows (28.9 cubic ft. persecond (cfs)) was calculated to be 1,702 pounds per day (lbs./day) as Total Suspended Solids(TSS) (Table 2). The Measured Load was estimated to be 6,959 lbs./day. Using a 10% explicitMOS, the Load Reduction necessary is 5,257 lbs./day. During the Summer-Fall seasonal flows(13.1 cfs), the target load capacity was calculated to be 681 lbs./day. The Measured Load is 2,509lbs./day. Using a 25% MOS, the Load Reduction necessary is 1,828 lbs./day.

Table 2 TMDL Summary Table For The Little Colorado River

WINTER-SPRING FLOWS (FEB-MAY) SUMMER-FALL FLOWS (JUN-SEP)Designed for 28.9 cfs (18.9 mgd) Designed for 13.1 cfs (8.5 mgd)Background, lbs./day TSS 354 Background, lbs./day TSS 354Waste Load Allocation, lbs./day TSS 0 Waste Load Allocation, lbs./day TSS 0Load Allocation, lbs./day TSS 1,225 Load Allocation, lbs./day TSS 262Margin of Safety, lbs./day TSS 123 Margin of Safety, lbs./day TSS 65TMDL, lbs./day TSS 1,702 TMDL, lbs./day TSS 681Measured Load, lbs./day TSS 6,959 Measured Load, lbs./day TSS 2,509Load Reduction, lbs./day TSS 5,257 Load Reduction, lbs./day TSS 1,828

Implementation projects and best management practices (BMPs) should be aimed at decreasing thecontributions of sediment during higher flow events. Effective methods include increasing riparianvegetation, stream bank stabilization, promotion of flood plain development, and minimization of theimpact of cattle in the general area. This can be accomplished by watershed improvements onuplands and riparian areas, road maintenance or closures, and improved grazing strategies andpractices.


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Figure 1 Project Area


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1 BACKGROUND INFORMATION

1.1 GeographyThe LCR is located in southern Apache County, AZ, near the border with New Mexico. The headwaters originate in the White Mountains along the northern and eastern slopes ofMount Baldy (11,403 ft.) (Fig. 1). The river flows east-northeast until it reaches Eagar,AZ, where it turns to a more northerly course.

1.2 GeologyThe rugged upper part of the watershed near Mount Baldy is mid to late Tertiary volcanics(Reynolds, 1988). The listed reach flows mainly through upper Tertiary and upperQuaternary volcanics (Reynolds, 1988). The area is also the site of the Springervillevolcanic field, which contains over 380 cinder cones and flows (ASU, 2001). Soils in thestudy area generally fall into three categories: 1) sandy on steep slopes around Greer; 2)shallow, basaltic, and stony near the South Fork confluence; 3) alluvial, with higher clayconcentrations in the Springerville/Eagar vicinity (ADEQ, 1982).

1.3 HydrologyThe LCR watershed above Lyman Lake drains approximately 774 square miles (ArizonaDepartment of Health Services (ADHS), 1982). The LCR is a perennial stream thatresponds primarily to two seasonal events: a Winter-Spring snowmelt and rain season fromFebruary to mid-May and a Summer-Fall monsoon event season from June throughSeptember. Two USGS gauge stations are present on LCR. USGS gage # 09384000 islocated above Lyman Lake, near St. John’s, AZ, and USGS Gage # 09383400 is locatednear Greer, AZ. The major tributaries to the LCR are South Fork, Grapevine Creek,Water Canyon Creek, Nutrioso Creek, and Carnero Creek. The stream portions abovethe confluence with South Fork are generally steep and store little sediment. Below theconfluence with South Fork, the gradient and steam velocity decreases.Data from over 60 years of record (1940 to 2000) for USGS gage station #09384000,above Lyman Lake, were used to calculate the average flow for each day of the year. Winter –Spring season (Nov 1 to May 31) flow values average 28.9 cfs. The average flowfor the Summer-Fall season (Jun 1 to Oct 31) is 13.1 cfs. The average base flow was alsocalculated and found to be 11.0 cfs, however the calculations were not carried over to theaverage base flow value, because these Winter-Spring and Summer-Fall TMDL valuesrepresent the critical condition for the LCR for sediment and, thus, turbidity impairments.


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Elevation approx. 8000 ft. Elevation approx. 6500 ft.

1.4 ClimateClimate varies greatly throughout the reach. The higher elevations generally receive moreprecipitation (annual average of 23.39 inches (in.) near Greer, AZ and 12 in. nearSpringerville, AZ). Precipitation is primarily rain and snow in the higher elevations and rainin the lower elevations. Summers in the higher elevations are warm in the day, averaging amaximum of 76Ein July, and cool at night, averaging a minimum of 47Ein July. Summers inthe lower elevations are often hot, averaging a maximum of 82-90Ein the day and, at night,averaging a minimum of 51-57Ein July.

1.5 VegetationThe LCR transects many ecosystems (Fig. 2). Vegetative species are predominantlyspruces and firs above 9,500 ft., ponderosa pines and mixed conifers above 8,000 ft, andpinon pine/juniper and grasslands at the lower elevations. A very marked transitionbetween the pines and the grasslands occurs around 7,400 ft. (ADHS, 1982).

1.6 Land UseAccording to the land ownership information provided by Arizona Land ResourceInformation System (ALRIS), the LCR watershed is a mixture of Federal, State, andprivate lands (Fig. 3). Land ownership is comprised of 45% United State Forest Service(USFS) Apache-Sitgreaves National Forest lands, 37% Arizona State Trust lands, and17% private party ownership. The remaining 1% is ArizonaGame and Fish Department(AGFD), Bureau of LandManagement (BLM), and WhiteMountain Apache lands. Themajor land use along the listedreach is agriculture and openrange. Figure 4 shows land usetype and percentage of total area.

Figure 2 Representative Ecosystems


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Figure 3 Land Ownership


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Figure 4 Land Use


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2 ENDPOINT IDENTIFICATION

2.1 Turbidity and the Linkage of Water Quality Standards and PollutantsThe United States Environmental Protection Agency’s (USEPA’s) recommended approachto the development of TMDLs with limited data is to develop estimates comprised of thebest methods and data available (USEPA, 1999).

Turbidity is a measure of the refraction of light, caused by the scattering of the photons, as itpasses through a sample of water. Although this can be due to a variety of causes, theturbidity standard was created as an indirect measure to protect aquatic life from impactsdue to excessive sedimentation and excessive algal blooms.

2.2 Identification and Description of Pollutant SourcesIn the 1998 303(d) list, the LCR is listed as impaired for turbidity from Water CanyonCreek to Carnero Creek (ADEQ, 1998) (Table 1). From June to October 2000, ADEQconducted a turbidity study of the LCR. Eighteen monitoring sites (Fig. 1) were establishedfrom the intersection of the Highways 260 and 373 (near Greer) and the LCR (Site 0) tothe end of the listed reach (Site 140). The sample sites were selected to better definesources of turbidity. Sample results are included in Appendix A. The results indicate thatthe turbidity impairment actually starts upstream of the confluence with Water CreekCanyon (near Site 35).

2.2.1 Point SourcesNo point sources were found on the LCR during ADEQ’s investigations. Therehave been no National Pollutant Discharge Elimination System (NPDES) permitsissued for this stretch of the river system.

2.2.2 Non-Point SourcesThe turbidity impairment in the LCR is a result of excessive sediment from naturaland anthropogenic sources that is flushed into the LCR system. A number ofpossible sources were identified during the field investigations.

2.2.2.1 Grazing and WildlifeUngulate grazing can contribute sediment to the system by disruption of thesoil surface, soil compaction, removal of organic matter, and trailing. Whenungulates overuse an area, there is the potential for increased soil loss,compaction, and accelerated overland flow. In riparian areas, grazing canreduce riparian vegetation, destabilize banks, and cause in-streamdisturbances that reduce the functionality of the stream.

The free range grazing practices of the turn of the century had drasticimpacts on the soil and vegetation of the LCR watershed (ADEQ, 2000).


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Today, livestock still graze most of the watershed. Even though grazingpractices have improved, improper livestock grazing is a source of finegrained sediment.

2.2.2.2 Stream Channel InstabilitiesThis portion of the LCR also suffers from a lack of riparian vegetation. Theabsence of vegetation in the stream course, which naturally slows the flow,contributes to higher velocities during high flows (Snyder, 1994). Thiscauses down cutting of the stream. Down cutting of the channel creates aloss in flood plain for the stream which means that during high flows, like thecritical flows, stream velocities are increased, thus increasing the shearstress/force acting upon the stream banks and increasing the erosionalforces.

2.2.2.3 Road SystemsThe USFS is mandated to maintain its system roads to certain standards. However, non-system roads created by recreationists undermine USFSefforts. The USFS expends much effort on closing non-system roads andreducing off-road travel; however, adequate funding is not always available.Other public roads are also a source of sediment. Road cuts, bridges,culverts, and other transportation features also impact the LCR.

2.2.2.4 Golf CourseThe recent construction of a golf course on the LCR (Sites 70, 76, and 78)contributed sediment to the river. The golf course received a notice ofviolation from the ADEQ for violation of the surface WQS for turbidity. The golf course altered construction practices and implemented otherBMPs to control sediment delivery to the LCR. Even though the golfcourse construction has been completed, there are several stretches of riverwithin the property boundaries that would benefit from stream stabilizationrestoration.

2.2.2.5 Natural ConditionsNatural sediment contributions can be the result of geologic formations andprocesses and their interactions with the vegetation, soils, and wildlife. Inaddition to out-of-stream contributions, fine sediment which has beenstored within the void spaces of larger bed materials, and flood plains andpoint bars, can be a source of turbidity. During large flow events, these finesediments are re-suspended and transported further down the system. Organic suspended materials and organisms present in the water columncan also effect the turbidity readings themselves by scattering the light of theturbidity meter in the same manner as suspended solids.

2.3 TMDL Calculation


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020

4060

80100

120140

0 10 20 30 40 50 60

Turbidity (NTU)

TSS

(mg/

L)

Figure 5 Winter-Spring, TSS vs. Turbidity

Turbidity is not easily transferred into the TMDL framework because it is a dimensionlessunit. Because of this, site specific TSS versus turbidity correlations were created for thisTMDL. These correlations link TSS values in mg/L to turbidity standards andmeasurements. Target Load Reductions of TSS will equate to reductions of turbidity.This is useful as the increased turbidity during high flows is caused by higher TSS due toincreased stream water velocities, shear stress, and stream power, which all result in highererosional forces.

2.3.1 TSS EquationsThe correlation graphs, and the resulting equations, are based on data obtainedthrough field measurements, laboratory results for TSS, and historic records. Thiscorrelation allows a numeric estimate of the amount of sediment and turbiditypresent in the stream during critical flows. Two sets of data were created: aWinter-Spring set and a Summer-Fall set. This allows for the creation of a set ofregressions and correlations that better represent seasonal conditions, and allow forthe creation of more valid regressions between the data points. The average flowvalues were used to calculate a corresponding turbidity and TSS reading by utilizingthe Turbidity & TSS vs. Discharge graphs and the TSS vs. Turbidity graphs.

Taken from the solution to the line best fitting the data in Figure 5, Winter-Spring, TSS vs.Turbidity

TSS=1.8726(turbidity) – 7.8851, R2=0.7008 Equation 1

Taken from the solution to the line best fitting the data in Figure 6, Winter-Spring, TSS andTurbidity vs. Flow

TSS = 1.4232(Q) + 3.0976, R2=0.8327 Equation 2


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0

20

40

60

80

100

120

140

0 10 20 30 40 50 60 70 80 90

Flow (cfs)

TSS

(mg/

L)

0

20

40

60

80

100

Tu

rbid

ity (

NT

U)

TSS

TurbidityLinear (TSS )

Figure 6 Winter-Spring, TSS and Turbidity vs. Flow

0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140

Turbidity (NTU)

TSS

(mg/

L)

Figure 7 Summer-Fall, TSS vs. Turbidity

Taken from the solution to the line best fitting the data in Figure 7, Summer-Fall, TSS vs.Turbidity

TSS=0.9644(turbidity), R2=0.8055 Equation 3

Taken from the solution to the line best fitting the data in Figure 8, Summer-Fall, TSS andTurbidity vs. Flow

TSS = 1.2616(Q) + 18.874, R2=0.1682 Equation 4


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0

20

40

60

80

100

120

140

0 5 10 15 20 25 30 35 40 45

Flow (cfs)

TSS

(mg/

L)

0

20

40

60

80

100

120

Tu

rbid

ity

(NT

U)

TSSAvg TurbLinear (TSS)

Figure 8 Summer-Fall, TSS and Turbidity vs. Flow2.

3.2 Background Site Location and ValuesIn order to determine the natural background sediment load value, a search wasconducted to identify another watershed consisting of the same geography, geology,hydrology, vegetation, channel morphology, and watershed size as the LCRwatershed. Criteria for the search included:

1.) The potential site must lie within, or tributary to, the LCRwatershed

2.) Must be an unlisted (303(d)) water body for exceedances of thesurface water quality turbidity standard

3.) It should have no, or few, anthropogenic disturbances within it’swatershed boundary

4.) There should be a sufficient amount of TSS and discharge data toperform the necessary calculations

No suitable site could be found that was near the same watershed size or flowregime as the LCR. Therefore, the search was modified to identify any relativelyundisturbed, or unlisted, segment within the watershed, or a tributary to the LCR,that could be used to approximate natural background values. A section of theLCR was used to calculate the natural background values. The natural backgroundconditions for sediment for the LCR were estimated by using two samplinglocations upstream of identified nonpoint sources, and above the 303(d) listedsegments of the LCR. These sample stations, 10 and 30 (Fig. 1), maintain thesame geologic, hydrologic, and geomorphic conditions as the listed reach of theLCR. The channel is approximately the same size, and flows at the sampling


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stations correspond well to flows in the main channel of the listed segment. Toarrive at a value for the background load for sediment, the turbidity values fromthese sampling stations were averaged and correlated into a Total SuspendedSolids value, and then calculated into a daily load.

The average of the turbidity readings taken by ADEQ at these sample stationsthrough the TMDL sampling plan, was 6.2 NTU. These values were taken in thesummer-fall season, so Equation 3 was used to calculate the corresponding TSSconcentration of 5.9 mg/L. To convert the 5.9 mg/L into a daily load value forTSS, 5.9 mg/L TSS was input into the following equation.

Flow (mgd) x average TSS (mg./L) x 8.341 = Background, TSS (lbs./day)

TABLE 3 CALCULATION OF BACKGROUND VALUE

Flow (cfs) Flow (mgd) TSS (mg/L) Background, TSS (lbs./day)11.02 7.2 5.93 354

1 8.34 is a conversion factor to transform mg/L to lbs./day, the units are (lbs.)(L)/(mg)(106 gallons)2 Average flow values taken from USGS Gage Station 09384000, from 1940-20003 Calculated value based on turbidity samples

2.3.3 Consideration of Seasonal VariationThe LCR experiences three distinct flow regimes (Fig. 9): a Winter-Springsnowmelt and rain season, a Summer-Fall monsoon storm season, and the baseflow conditions that occur at other times of the year. For this report data wassorted into two categories, Winter-Spring season, and Summer-Fall season. TheWinter-Spring data has higher overall flows, a larger contributing sediment load,and is more sustained over the duration of the season. The Summer-Fall monsoonstorm driven flows are highly variable dependent on location and storm intensity.

To take into consideration this discharge variation, and address the differences inthe correlations between TSS and turbidity and flow, the TMDL values werecalculated for each season. The average flow values were used to calculate acorresponding turbidity and TSS reading by utilizing the TSS and Turbidity vs.Discharge graphs (Figs. 6 and 8) and the TSS vs. Turbidity graphs (Figs. 5 and 7).


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Daily Average Discharge (1940 - 2000) for the Little Colorado River

0

20

40

60

80

100

120

D e c Jan Feb Mar Apr May J u n Jul A u g Sep Oct Nov D e c

D a y

USGS Gage 09384000USGS Gage 09383400

Figure 9

2.3.4 Margin of SafetyThe MOS for this TMDL is different for the two seasons due to uncertainty in thecorrelations and regression analysis. For the Winter-Spring season, where arelatively sound regression was created between TSS and turbidity, and TSS anddischarge, the MOS was set to be 10% of the LA value. For the Summer-Fallseason, where a relatively sound regression was created between TSS andturbidity, but a large amount of scatter created an unreliable relationship betweenTSS and discharge, the MOS was set to be 25% of the LA value. These explicitMOS values account for errors in calculating the critical and average flows, theinnate errors present in the correlation of TSS and turbidity with discharge, thepossible error in the estimate of natural background values, and for the accuracy ofthe measurements and instruments.

2.3.5 Winter-Spring Flow Based TMDL ValuesThe following TMDL calculations are based upon the average Winter-Spring flowvalue of 28.9 cfs, which is based on 60 years of available data from the USGSgage station above Lyman Lake.

Calculation of Target Load Capacity (lbs. of TSS per day) for Winter-Spring FlowsFlow (mgd) x TSS target (mg/L) x 8.34

1 = Target Load Capacity, TSS (lbs./day)


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Table 4 Calculation of Target Load for Winter-Spring FlowsFlow(cfs)

Flow(mgd)

Turbidity Std.(NTU)

TSS target(mg/L)

Target Load, TSS(lbs./day)

28.92 18.9 10.03 10.84 17021 8.34 is a conversion factor to transform mg/L to lbs./day, the units are (lbs.)(L)/(mg)(106 gallons)

2 Average flow values during the Winter-Spring flows (Nov 1 – May 31), data appeared in Graph 1; average dischargefrom 1940-20003 Arizona Aquatic and Wildlife cold-water stream surface WQS for turbidity is 10 NTU4 Calculated using Equation 1, Winter – Spring TSS vs. Turbidity, and inputting the turbidity value of 10 NTU

Calculation of Little Colorado River TMDL for Winter-Spring FlowsTMDL as TSS (lbs./day) = WLA + LA + BG + MOS

MOS + LA = TMDL — WLA—BG, but, MOS = 0.10(LA)0.10(LA) + 1(LA) = TMDL — WLA—BG

LA = (TMDL — WLA—BG)/(1.10)

Table 5 Calculation of TMDL for Winter-Spring FlowsWLA

(lbs./day)LA (lbs./day) Background

(lbs./day)MOS, 10%(lbs./day)

TMDL(lbs./day)

0 1225 3541 1232 17021 This value was calculated earlier in section 2.3.2

2 MOS is 10% of the LA to accommodate for errors in data, graphical interpretations, and calculations of values

Calculation of the Measured** Load for Winter-Spring FlowsFlow (mgd) x Measured** TSS (mg./L) x 8.341 = Measured** Load, TSS (lbs./day)

Table 6 Calculation of Measured** Loads for Winter-Spring FlowsFlow (cfs)

Flow(mgd)

Measured** Turbidity(NTU)

Measured**TSS (mg/L)

Measured** Load,TSS (lbs./day)

28.92 18.9 27.83 44.24 6959** The term "Measured" refers to average Winter – Spring high flow values which were estimated using the correlationgraphs, and aren’t representative of actual field measurements.1 8.34 is a conversion factor to transform mg/L to lbs./day, the units are (lbs.)(L)/(mg)(106 gallons)2 Average flow values during Winter-Spring flows as identified in graph 1

3 Calculated using Equation 1, TSS vs. Turbidity, and inputting the TSS value 44.2 mg/L4 Calculated using Equation 2, Winter – Spring Discharge vs. Turbidity & TSS, and inputting a flow of 28.9 cfs

Calculation of TSS Load Reduction (lbs. per day) for Winter-spring flowsMeasured** Load, TSS - Target Load, TSS = Load Reduction, TSS (lbs./day)


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Table 7 Calculation of Load Reductions for Winter-Spring FlowsMeasured** Load, TSS

(lbs./day)Target Load, TSS

(lbs./day)Load Reduction, TSS

(lbs./day)6,959 1,702 5,257

** The term "Measured" refers to average Winter – Spring high flow values which were estimated using the correlation

graphs and aren’t representative of actual field measurements.

2.3.6 Summer-Fall Flow Based TMDL ValuesThe following TMDL calculations are based upon the average Summer-Fall flow value of13.1 cfs. Recalculation of the TMDL values using the average flow value of 13.1 cfs alsorequires the use of the corresponding Summer – Fall correlations and equations.

Calculation of Target TSS Load, adjusted for Summer-Fall FlowsFlow (mgd) x TSS target (mg/L) x 8.341 = Target Load Capacity, TSS (lbs./day)

Table 8 Calculation of Target Load for Summer-Fall FlowsFlow(cfs)

Flow(mgd)

Turbidity Std.(NTU)

TSS target(mg/L)

Target Load, TSS(lbs./day)

13.12 8.5 10.03 9.64 6811 8.34 is a conversion factor to transform mg/L to lbs./day, the units are (lbs.)(L)/(mg)(10 6 gallons)2 Average flow values during the Summer-Fall flows (June 1 – Oct 31), data appeared in Graph 1; average discharge

from1940-2000

3 Arizona Aquatic and Wildlife cold-water stream surface WQS for turbidity is 10 NTU4 Calculated using Equation 3, Summer – Fall, TSS vs. Turbidity, and inputting the turbidity value of 10 NTU

Calculation of TMDL during Summer-Fall Flow conditionsTMDL as TSS (lbs./day) = WLA + LA + BG + MOS

MOS + LA = TMDL — WLA—BG but, MOS =0.25LA)0.25(LA) + 1(LA) = TMDL — WLA—BG

LA = (TMDL — WLA—BG )/(1.25)

Table 9 Calculation of TMDL for Summer-Fall FlowsWLA

(lbs./day)LA

(lbs./day)Background

(lbs./day)MOS, 25%(lbs./day)

TMDL(lbs./day)

0 262 3541 652 6811 This value was calculated earlier in section 2.3.2.

2 MOS is 25% of the LA to accommodate for errors in data, graphical interpretations, regressions, and calculations of

values


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Calculation of the Measured** Load for Summer-Fall Flow conditionsFlow (mgd) x Measured** TSS (mg/L) x 8.341 = Measured** Load, TSS (lbs./day)

Table 10 Calculation of Measured** Loads for Summer-Fall FlowsFlow (cfs) Flow

(mgd)Measured** Turbidity

(NTU)Measured**TSS (mg/L)

Measured** Load,TSS (lbs./day)

13.12 8.5 36.73 35.44 2509** The term "Measured" refers to average Summer-Fall high flow values which were estimated using the correlation

graphs, and aren’t representative of actual field measurements.

1 8.34 is a conversion factor to transform mg/L to lbs./day, the units are (lbs.)(L)/(mg)(10 6 gallons)

2 Average flow values during Summer-Fall flows as identified in graph 1

3 Calculated using Equation 3, Summer – Fall, TSS vs. Turbidity, and inputting the TSS value 35.4 mg/L

4 Calculated using Equation 4, Summer – Fall, Discharge vs. Turbidity & TSS, and inputting the avg. Summer – Fall

flow of 13.1 cfs

Calculation of Load Reductions for Summer-Fall Flow conditionsMeasured** Load, TSS - Target Load, TSS = Load Reduction, TSS (lbs./day)

Table 11 Calculation of Load Reductions for Summer-Fall FlowsMeasured** Load, TSS

(lbs./day)Target Load, TSS

(lbs./day)Load Reduction, TSS

(lbs./day)2,509 681 1828

** The term "Measured" refers to average Summer-Fall high flow values which were estimated using the correlation

graphs, and aren’t representative of actual field measurements.

2.4 Waste Load AllocationsNo point sources for turbidity were found to be present on the LCR during ADEQ’ssampling efforts and investigations. There have been no National Pollutant DischargeElimination System (NPDES) permits issued for this section of the river system. Therefore,the WLA for all TMDL calculations is zero.

2.5 Load AllocationsComparison of the different seasons indicates that the Winter-Spring season is responsiblefor more sediment delivery to the LCR than the Summer-Fall flows. LAs were based onthe Winter-Spring TMDL values and subdivided by potential source. The potential sourceswere grouped into categories, based on field observations, to allow for smaller allocations. This will make it possible to set goals and judge the effectiveness of implementation plans. The values are presented in the following table.


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Table 12 Load Allocations and Load Reduction Targets by SourceType of potential source Percent contributing to

the TMDL LoadAllocation

Load value(lbs./day TSS)

PercentReductionin Loading

LoadReduction

(lbs./day TSS)

Percent oftotal loadreductionnecessaryas per theTMDL

Grazing Practices 60 4,175 75 3,132 60Stream ChannelInstabilities

15 1,044 65 679 13

Road Cuts 5 348 55 191 4Golf Course 5 348 85 296 6Streambed Load 5 348 55 191 4Natural Conditions 10 696 0 0 0TOTAL 100% (6,959) 6,959 N/A 4,420 85%

(5,257)

The overall load reduction needed to comply with current Arizona WQSs is approximately5,257 lbs./day of sediment during the critical Winter-Spring flows. However, the recentlycompleted and approved Nutrioso Creek TMDL for turbidity contains an implementationplan that targets an overall reduction of approximately 837 lbs./day of sediment during thecritical Spring flow. As Nutrioso Creek is tributary to the LCR, this load reduction wassubtracted from the needed reduction in the LCR to 4,420 lbs./day.


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3 IMPLEMENTATIONBy focusing most of the implementation on the larger values obtained from the Winter-Springrelationships, it can be assured that compliance with the TMDL will lead to the LCR meeting andmaintaining Arizona’s surface WQSs for turbidity. Private landowners as well as state and federalland managers can apply for grants and seek assistance in securing finances and technical expertisein meeting and maintaining the goals set forth in this report. Possible TMDL implementationstrategies include the following:

1. Increase education and public awareness to local landowners through outreach andwatershed group activities

2. Create milestones for each BMP and project and evaluate effectiveness asnecessary

3. Decrease stream velocities during critical flow events by:a) Increasing willow vegetationb) Placing stream grade stabilization structuresc) Increasing the flood plain (i.e. adding point bars)

4. Decrease sheet flow and wind erosion contributions to tributaries and listedsegments of the LCR by:

a) Removing rabbitbrushb) Increasing density of grasses as land cover

5. Prevent stream channel down cutting and promote stabilization by:a) Removing cattle and wildlife from the stream channel during critical flowperiodsb) Allowing cattle to graze only in the dormant winter months, under arange management systemc) Re-vegetating the stream channeld) Using stream restoration techniques to speed up recovery of streamcorridor

3.1 Best Management PracticesA variety of BMPs can be utilized as part of the implementation strategy to reduce sedimentloading to the LCR.

Cattle grazing in the riparian corridor could be confined to only the dormant winter months,which would allow the emergent plants in the spring to grow and take hold. It would alsoallow for a greater diversity of plant communities in the riparian corridor, which will helpestablish more protective cover for the erosive soils and act as stream energy dissipatersduring higher flows. The BLM recommends winter grazing because the cattle’s hoof actioncompacts soils and adds in nutrients. Also, the cattle will feed on the mature old growthallowing room in the spring for the new growth to occur and compete for resources(BLM,1989). The USFS recommends that winter grazing maintain adequate stubble heightof the vegetation going into the spring growing season (ADEQ, 2000).

The USFS Apache-Sitgreaves is a primary landowner in the project area. They arecommitted to improving the land resources within their jurisdiction and have several


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projects ongoing within the watershed (ADEQ, 2000). Some of these projects include:reduced logging, road closures, and revisions in grazing allotments.

The Apache-Sitgreaves National Forest has already implemented, or plans to implement, avariety of BMPs on lands under their jurisdiction including: 1) reduced logging; 2) roadclosures – 40 miles of roads were closed as an erosional control measure in 1999; and 3)the forest instituted the following grazing allotment revisions:

• Adjusted cattle entry times and densities

• Since 1995, they have had a 66% reduction in cattle numbers on the AlpineDistrict

• A goal to balance the permitted numbers with the allowable use by 2005 inall Apache-Sitgreaves National Forest Grazing Allotments

The management of ungulate wildlife populations is the jurisdiction of AGFD. For GameManagement Unit (GMU) 1, in which this portion of the LCR watershed is located, elkpopulation numbers have declined approximately 42% since 1994. The AGFD hasimplemented a monitoring program to assess herbaceous forage utilization by elk in keyareas in all GMUs within Region I. This information enables the Department to incorporatehabitat-based parameters into annual population management objectives for elk. Themonitoring data indicated high utilization in localized areas of the LCR by elk. To addressutilization concerns, the AGFD has proactively implemented management strategies duringthe last several years with the objective of reducing the elk population in GMU 1. As notedabove, these strategies have resulted in substantial reductions since the mid-1990's. Thesuccess of these strategies is dependent on a variety of factors including habitat conditionand available forage. The AGFD actively manages ungulate wildlife populations within thewatershed. The AGFD monitors herbaceous forage usage of elk, the primary wildlifeungulate, to assist in population management strategies. Active management strategiesenacted over the last several years have resulted in an approximate 42% reduction in thenumber of elk (AGFD, 2002).

The large sector of private lands also needs to be addressed. Additional projects andBMPs for use on private lands will be important in the future.

Several implementation practices and projects have been undertaken on Nutrioso Creek, atributary to the LCR, that could be beneficial if applied to other areas within the LCR listedreach. Some of these projects include:

• In areas where historic overgrazing has occurred, private landowners havefenced off the riparian corridor to keep out cattle and elk during criticalgrowing periods.


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• Stream grade stabilization structures have been installed to help protect theat risk banks during high critical flow events. These structures will also helpdissipate stream velocities and thus dissipate stream energy and erosionalforces during high flows (ADEQ, 2000).

• Stream restoration projects have been undertaken to speed up thedevelopment of an in-channel flood plain, increase sinuosity, etc. It isimportant to note, while these projects have created a more immediateimpact on improving water quality during critical flow, they are more costlyand severe to implement.

• Off channel water wells and wildlife drinkers have allowed for more waterto remain in the stream itself and allow for the riparian corridor to be fencedoff without water-gaps for wildlife and cattle to access the stream fordrinking purposes. This has allowed for irrigation of the re-vegetationprojects along the stream corridor. However, caution should be used in theplacement of these structures. While reducing water withdrawals fromstream channels is commendable goal, a shift to groundwater use, if itresults in an overall increase in water use, could result in a lowered watertable, which could in turn negatively affect in-stream flows (AGFD, 2002).

• The riparian corridor has been re-vegetated with willow plantings and grassseeds using a Critical Area Planting method as outlined by the NaturalResources Conservation Service. These plantings have been supplementedwith sprinkler irrigated waters until they took hold on the established banksand stream course. The plantings on the upland areas beyond the streamcorridor were sprinkler irrigated until the root were established enough toreach the moisture in the soils. These plantings have helped protect theerosive soils and act to dissipate stream energy during critical flow (ADEQ,2000).

• Sprinkler irrigation systems combined with a poly pipe to line the irrigationditch have increased irrigation efficiencies and allowed for more water tostay in the stream and thus increase the streamflow year round. Combinedwith other projects and aspects of implementation these tools have allowedfor effective revegetation and removal of cattle and wildlife from the streamcourse for the majority of the year by creating more forage in the managedrangeland and an alternative water source created from the groundwaterwells.

• Rabbitbrush eradication projects have been undertaken on someproperties. By removing the rabbitbrush and replacing it with grassseeding, more grass per acre has been created for cattle consumption,reducing their reliance on the riparian vegetation of the stream corridor and


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allowing for their removal from the riparian corridor with the use of fencesand range management plans. From a watershed standpoint the removal ofrabbitbrush and reintroduction of grasses improves species diversity andcomposition. Also, the grasses provide a more stable root mass than therabbitbrush, thus increasing the soil stability of the rangelands anddecreasing the amount of sediment contributed from sheet flow and winderosion over these rangelands.

3.2 MONITORING PLANADEQ staff will continue to monitor turbidity, TSS, flow, and stream morphology over thenext several years during varied flow stages. The LCR watershed is scheduled for moreintensive ambient monitoring as a part of the Fixed Station Network (FSN) rotatingwatershed approach in 2006. This approach targets two watersheds each year over a fiveyear period. ADEQ will monitor water quality and physical integrity of the LCR usingtechniques such as :

• Historic photo monitoring sites that are present, which can be utilized forfuture comparisons.

• Aerial photography to monitor vegetative cover.

• Stream channel cross sections to assess changes in channel morphology.

• Permanent follow-up monitoring sites to perform trend analyses.

Macroinvertebrate sampling may also be undertaken in order to obtain the necessaryinformation to calculate an Index of Biological Integrity score. This information will allowfor a more direct measure of the health of the LCR aquatic ecosystem. This data willaugment the turbidity and TSS data as it is a more direct measure of stream health for waterdesignated as Aquatic and Wildlife cold (A&Wc). This data will also allow for the re-evaluation of the implementation strategies, milestones, and goals.

Potential volunteer monitoring of native threatened and endangered aquatic species and thedisplacement, or die-off, of introduced aquatic species would contribute valuable data. Thiscould help to guide implementation, future BMPs, and the re-evaluation of this TMDL andthe milestones set forth. Volunteer monitoring of discharge, turbidity, and TSS, along witherosional and sedimentation features, could be of assistance in the future for re-evaluationand assessment of the goals and values set forth, as well as to track progress of theimplementation plan.

3.3 Time LineThe LCR TMDL will use a phased approach to TMDL implementation. Watershedprojects will be started incrementally as they are funded. The time frame forimplementation is estimated to be 10 years (Table 13). Therefore the timeframe estimated


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for the LCR to meet the turbidity standard during critical flows is approximately 15 - 30years, depending upon the amount and the duration of flow events in the LCR. TheUSEPA recognizes that sediment TMDLs with primarily non-point sources of pollution canbe difficult to manage, and that these problems are often generated over multiplegenerations and may require as long to correct (USEPA, 1999).

Table 13 Estimated Implementation Schedule YEAR

ACTIVITY 1 2 3 4 5 6 7 8 9 10

Public outreach & involvement X X X X X X X X X XEstablish Milestones X X XSecure project funding, as needed X X X X X X X X X X

Best Management Practices X X X X X X X X X XDetermine BMPs effectiveness X X XReevaluate Milestones and strategies X X

3.4 MilestonesMilestones will be used to determine if control measures and BMPs are having a positiveimpact on reducing turbidity and the erosional forces present in the LCR. Variousmeasures will be utilized as milestones to measure the success of the projects and theBMPs. This could include an increased amount of natural vegetation in the stream course,a more stable channel geometry, lowered stream velocities, lower TSS and turbidity valuesduring higher discharges, and more balanced TSS and turbidity values during different flowregimes. The milestones will be reevaluated periodically to determine their validity andeffectiveness as more data is available for analysis.

3.5 AssurancesArizona Revised Statutes do not provide for enforceable actions to be taken against non-point sources of pollution. Implementation plans for nonpoint source TMDLs dependsolely upon the volunteer approach of land managers, in implementing projects and BMPs. Cooperation of State and Federal Agencies and private landowners will be paramount inthe implementation of this TMDL. ADEQ has grant funding available, as do other agencies,to help with the implementation of watershed restoration strategies.

4 PUBLIC PARTICIPATION

4.1 Public Participation in the TMDL ProcessPublic participation occurred during data collection, background information, and indeveloping this report. In March 2002, the draft TMDL was made available for a 30-daypublic comment period. Public notice of the availability of the draft document was postedin a newspaper of general circulation (The White Mountain Independent), emailnotifications, phone calls, and webpage postings. The LCR TMDL Draft was presented tothe Upper Little Colorado River Watershed Group in their March 28, 2002 meeting.


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No comments were received during the public notice. This TMDL was published in theArizona Administrative Register in May, 2002, in compliance with A.R.S. §49-231. Afterthe 45-day notice period has been completed, the TMDL will be forwarded to EPA forapproval.

4.2 Watershed GroupThe LCR Watershed Partnership was formed in November of 1998. The LCR WatershedPartnership incorporates concerned private citizens, private landowners, and otherinterested State and Federal Agency personnel. The watershed group will provideoversight for the implementation projects and plans, and may provide additional data in theform of volunteer monitoring of the stream.

ADEQ has a website at http://www.adeq.state.az.us/environ/water/assess that will provideinformation and links to other data relevant to this LCR TMDL and contact information.


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REFERENCESADEQ. Arizona’s 1998 Water Quality Limited Waters List (Arizona’s 303(d) List.) EQR-98-8 July 1998.

ADEQ. Nutrioso Creek TMDL. July 2000.

ADHS. The Little Colorado River Watershed above Lyman Lake: Water Chemistry,Nutrients, and Nutrient Standards. July 1982.

AGFD. Personal communication with John Kennedy. March 2002

Arizona State University. Department of Geology web page,http://geology.asu.edu/volc/az_volcs.

Bureau of Land Management. Grazing Management for Riparian-Wetlands Areas.TR 1737-11 1989.

Bureau of Land Management. Process for Assessing the Proper Functioning Condition. TR 1737-14 1997.

Bureau of Land Management. Process for Assessing the Proper Functioning Condition forLentic Riparian-Wetlands Areas. TR 1737-6 1992.

Bureau of Land Management. Management Techniques in Riparian Areas.TR 1737-3 1989.

Bureau of Land Management. Managing Change –Livestock Grazing on Western RiparianAreas. July 1993.

Bureau of Land Management. Riparian Area Management. TR 1737-9 1993.

Hyde, Peter. ADEQ. Elevated Fecal Coliform Levels in LCR and the LCR atEagar/Springerville, Apache County, May and June 1993. December 1994.

Reynolds, Stephen J. Geologic Map of Arizona. 1988.

Snyder, Bruce and Snyder, Janet. Engineering-Science, Inc. for ADEQ contract #343280S25. Analysis of Water Quality Functions of Riparian Vegetation. Oct. 1994.

USEPA. Protocol for Developing Sediment TMDL’s, 1st Edition. EPA 841-B-99-004 October 1999.

Little Colorado Turbidity Draft TMDL August 2002, ADEQ

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APPENDIX A

STATION

NUMBERDATE TURBIDITY VALUE (NTU) AVG. TURB. (NTU) FLOW(CFS) TSS(MG/L)

100329 08/21/90 1 1 1.74 5

10/19/90 0.8 0.8 2.46 4

06/19/91 1.32 1.32 23.52 6

08/07/91 1.38 1.38 4.6 5

10/09/91 0.49, 0.46 0.48 2.89 4

01/06/92 0.58 0.58 6.5 4

04/15/92 8.30, 10.00 9.15 6 4

06/10/92 2.10, 2.50 2.3 20.76 7

08/11/92 2.20, 1.05 1.63 6.15 10

10/18/94 0.79, 1.07 0.93 4.2 4

12/13/94 0.16, 0.16 0.16, 0.16 6 4

04/18/95 2.70, 3.48 3.09 8.9 9

06/07/95 1.50, 4.48 2.99 37.62 12

08/29/95 3.3 3.3

100328 11/11/87 1.55 1.55 8.42 5

01/13/88 0.71 0.71 5.54 2

02/17/88 3.8 3.8 5.77 2

04/12/88 3.9 3.9 17.79 5

06/22/88 0.96 0.96 12.13 8

09/14/88 1.9 1.9 13.2 5

10/18/88 0.9 0.9 6.1 14

11/08/88 0.8 0.8 5.7 4

12/13/88 1.1 1.1 5.3 2

01/09/89 1.4 1.4 5.7 8

02/15/89 0.71 0.71 3.9 2

04/10/89 4.2 4.2 12.9 26

05/08/89 2.5 2.5 11.6 4

06/06/89 0.4 0.4 5.1 2

07/10/89 0.83 0.83 3.9 10

07/31/89 1.7 1.7 5.6 4

09/14/89 0.9 0.9 7.9 4

10/26/93 0.65, 1.2 0.93 6.62 4

12/15/93 1.1, 1.68 1.4 5.78 4

02/10/94 0.97, 1.38 1.18 5.27 4

04/13/94 1.39, 1.87 1.63 7.74 4

06/14/94 1.2, 2.1 1.7 9.81 4


STATION


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100328 CONT 08/16/94 1.23, 1.88 1.56 6.16 4

10/18/94 0.78, 1.6 1.19 5.16 4

12/13/94 0.23, 2.2 1.22 6.27 4

02/22/95 2.9, 5.13 4 7.31 9

04/18/95 3.2, 3.74 3.5 22.1 7

06/06/95 2.1, 4.62 3.4 41.33 10

08/28/95 1.33, 3.41 2.37 17.08 5

10/30/95 0.63, 1.94 1.29 5.48 4

12/27/95 0.79, 3.47 2.13 5.53 4

02/22/96 0.93, 1.41 1.17 4.88 4

04/26/96 0.47, 3.20 1.84 5.53 4

06/18/96 0.86, 1.25 1.06 2.5 4

08/28/96 1.21, 1.19 1.2 4.88 7

04/13/99 6.97, 3.10 5.04 6.94

06/22/99 0.71, 1.54 1.13 4.64

08/24/99 2.13, 1.00 1.57 14.35

10/14/99 1.36, 0.97 1.17 5.28 4

03/30/00 2.00, 2.60 2.3 5.67

06/28/00 5.40, 2.70 4.05 5.53 10

0 06/20/00 11, 13.4 12.2

08/01/00 12.2, 12.4 12.3 0.31 20

09/27/00 5.52, 5.63 5.75 0.52 13

10/24/00 4.56, 3.48 4.02 0.85 10

10 06/20/00 3.24, 3.99 3.62

08/01/00 3.89, 6.04 4.97

09/27/00 7.9, 6.75 7.33 16

10/24/00 8.11, 7.9 8.01 6

100644 07/08/92 0.6, 0.4 0.5 5

06/16/93 0.8, 1.5, 0.6 1

06/08/95 1.7 1.7 0.3

06/02/98 0.94, 0.95 0.9

20 06/20/00 1.27, 1.32 1.3

08/01/00 1.04, 1.41 1.23

09/27/00 0.32, 0.65 0.49 1.43 8

10/24/00 2.77, 2.71 2.74 0.83

22 06/20/00 3.23, 2.88 3.06

08/01/00 2.64, 2.09 2.37


STATION


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22 CONT 09/27/00 1.99, 1.94 1.97 9

10/24/00 2.08, 2.48 2.28 8

30 06/20/00 7.05, 6.42 6.61

06/21/00 5.91, 5.73 8.31 6

06/23/00 6.46, 6.76 8.3 6

08/01/00 7.35, 6.72 7.04 4.66 4

09/27/00 5.96, 5.76 5.86 2.01 10

09/28/00 8.37, 8.24 8.31

10/24/00 7.52, 7.7 7.61 5.45 18

35 06/20/00 12.1, 12 12.05

08/01/00 24.3, 24.2 24.3 17

09/27/00 33, 31.8 32.4 36

10/24/00 24, 24.2 24.1 27

40 06/20/00 27.4, 27.9 27.7

08/01/00 30.4, 32.3, 33.2, 29.4 31.3 4.24 30

09/27/00 23.6, 22.9 23.25 0.73 21

10/24/00 31.5, 31.7 31.6 7.22 32

52 06/23/00 14.2, 13.2 13.7 9.34 24

06/21/00 18.6, 18.5 18.6 6.89 5

08/01/00 29.4, 27.9 28.7 3.78 23

09/27/00 14.7, 13.7 14.2 1.53 14

10/24/00 27.3, 26.4 26.85 21

70 06/21/00 17.9, 17.8 17.9

08/03/00 38, 36.2 37.1

09/27/00 15, 15.7 15.35

10/24/00 29.3, 27.8 28.55 34

76 06/21/00 14.5, 14.3 14.4

08/03/00 34.9, 34.7 34.8

09/27/00 15.1, 15.1 15.1

10/24/00 29.8, 29 29.4 33

78 06/21/00 14, 14.7 14.4

08/03/00 33.9, 32.8 33.4

9/27/00 14.4, 14.8 14.6 24

10/24/00 28.6, 29.1 28.85 47

80 06/21/00 28, 27.5 27.8

08/02/00 31.9, 30.5 31.2

09/27/00 16.4, 16.8 16.6 12


STATION


-33-

80 CONT 09/28/00 23, 22.6 22.8

10/25/00 26.6, 26.3 26.45 25

90 06/21/00 25.5, 24.4 25 2.31 26

06/23/00 21.2, 24.7 23

08/02/00 39.9, 39.4 39.7 1.44 38

09/27/00 31.6, 31.4 31.5 0.84 47

10/24/00 46.1, 46.7 46.4 50

100333 10/26/93 6, 12.3, 6.3 8.2 4.94 8

12/15/93 7, 7.06 7.03 1.78 4

02/10/94 5.5, 8.47 7 2.98 6

04/14/94 11.2, 12.7 12 15.07 14

06/02/94 8.7 8.7 2.66 15

06/14/94 8.6, 11.3 10 2.58 9

10/18/94 7.4, 9.99 8.7 7.15 5

12/13/94 3.5, 13.7 8.6 6.49 10

02/22/95 11.2, 15.6 13.4 13.99 11

04/18/95 7.2, 7.83 7.5 28.93 11

06/06/95 8.7, 11.5 10.1 6.78 19

08/29/95 53, 96.4 74.7 40.1 130

10/30/95 9.4, 13.2 11.3 4.378 12

12/27/95 6, 10 8 5.97 12

02/22/96 11.3, 18.3 14.8 4.11 18

04/24/96 12.2, 16.1 14.2 1.58 19

06/20/96 7.3, 11.3 9.3 0.8 12

08/28/96 22 ,38.3 30.15 4.55 53

100331 06/19/91 6.6 6.6 14.19 708/07/91 14.4 14.4 8.98 29

12/03/91 3.9, 6.3 5.1 1.17 14

10/09/91 9.4 9.4 0.25 16

02/19/92 6.2

06/11/92 43 55 17.12 21

08/11/92 12.5, 14 13.3 10.28 38

11/24/92 16.4, 24.5 20.5 7.12 14

03/16/93 46.5, 9.2 27.9 77.2 126

06/23/93 14.6, 47 30.8 13.14 17

04/13/99 7.9, 16.3 12.1 2.92 11

06/22/99 12.2, 7.3 9.8 2.16 5


STATION


-34-

100331 CONT 08/24/99 16.4, 10 13.2 36.72 16

10/14/99 9.51, 5.2 7.4 5.5 7

03/29/00 19, 22.6 20.8 14.53 40

06/28/00 10.2, 6.7 8.5 1.35 8

08/15/00 24, 44.5 34.3 2.18 42

100 06/21/00 9.96, 10.7 10.3

08/02/00 40, 38.8 39.4 1.46 27

09/28/00 34.8, 33.8 34.3 1.07 41

10/24/00 79.7, 76.9 78.3 7.93 60

108 09/27/00 41, 41.7 41.35

10/24/00 78, 74.3 76.15 63

109 08/02/00 32.9, 33.1 33 1.45 27

09/27/00 38.3, 39.1 38.7 0.63 29

10/24/00 71.4, 71.4 71.4 8.11 66

110 06/21/00 35.8, 34.4 35.1

09/27/00 51.3, 51.8, 56.7, 59.2 51.55, 57.95 0.56

10/24/00 76.2, 77.3 76.75 65

120 08/02/00 36.9, 35.5 36.2 0.85 32

09/28/00 45.6, 46.2 45.9 0.21 45

10/24/00 86, 85.3 85.65 9.13 66

130 06/22/00 33.5, 33.6, 34.6, 34.6 34.1

08/02/00 35.5, 33.5 34.5

09/28/00 35.9, 36.2 36.05

10/24/00 127, 128 127.5 110

140 06/21/00 28.9, 29.3 29.1

08/02/00 33.7, 32.6 33.2 1.16 32

09/28/00 16.7, 16.5 16.6 0.88

09/28/00 26.9, 27.9 27.4 15

10/24/00 108, 101 104.5 10.25 91

little colorado river tmdl for turbidity · september. two usgs gauge stations are present on lcr....

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